Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2SR - Regulating Packet Flow on a Per-Interface Basis---Using Generic Traffic Shaping [Cisco IOS Software Releases 12.2 SR]

Table Of Contents

Regulating Packet Flow on a Per-Interface Basis — Using Generic Traffic Shaping

Contents

Prerequisites for Configuring Generic Traffic Shaping

Restrictions for Configuring Generic Traffic Shaping

Information About Configuring Generic Traffic Shaping

Generic Traffic Shaping Functionality

Adaptive Generic Traffic Shaping on Frame Relay Networks

Benefits of Generic Traffic Shaping

How to Configure Generic Traffic Shaping

Configuring Generic Traffic Shaping on an Interface

Configuring Generic Traffic Shaping Using an Access Control List

Access Control List Functionality

Configuring Adaptive Generic Traffic Shaping for Frame Relay Networks

Configuration Examples for Generic Traffic Shaping

Generic Traffic Shaping on an Interface Configuration: Example

Generic Traffic Shaping Using an Access Control List Configuration: Example

Adaptive Generic Traffic Shaping for a Frame Relay Network Configuration: Example

Where to Go Next

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Generic Traffic Shaping

Regulating Packet Flow on a Per-Interface Basis — Using Generic Traffic Shaping

Packet flow on a network can be regulated using a traffic shaping mechanism. One such traffic shaping mechanism is a Cisco feature called Generic Traffic Shaping (GTS). Generic Traffic Shaping allows you to regulate the flow of packets going out an interface or subinterface, matching the packet flow to the speed of the interface. This module describes the concepts and tasks related to configuring Generic Traffic Shaping.

Module History

This module was first published on May 2, 2005, and last updated on May 2, 2005.

Finding Feature Information in This Module

Your Cisco IOS software release may not support all of the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Generic Traffic Shaping" section.

Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

•Prerequisites for Configuring Generic Traffic Shaping

•Restrictions for Configuring Generic Traffic Shaping

•Information About Configuring Generic Traffic Shaping

•How to Configure Generic Traffic Shaping

•Configuration Examples for Generic Traffic Shaping

•Where to Go Next

•Additional References

•Feature Information for Generic Traffic Shaping

Prerequisites for Configuring Generic Traffic Shaping

Knowledge

•Be familiar with the concepts in the "Regulating Packet Flow Using Traffic Shaping" module.

Platform Support

•Use Feature Navigator to determine if the platform in use supports GTS. Access Cisco Feature Navigator at http://www.cisco.com/go/fn.

Restrictions for Configuring Generic Traffic Shaping

•GTS is not supported on the following interfaces:

–Multilink PPP (MLP) interfaces

–Integrated Services Digital Networks (ISDNs), dialer interfaces, or generic routing encapsulation (GRE) tunnel interfaces on the Cisco 7500 series router

•GTS is not supported with flow switching.

Information About Configuring Generic Traffic Shaping

To configure GTS, you should understand the following concepts:

•Generic Traffic Shaping Functionality

•Adaptive Generic Traffic Shaping on Frame Relay Networks

•Benefits of Generic Traffic Shaping

Generic Traffic Shaping Functionality

GTS is a traffic shaping mechanism (also known as a "traffic shaper"). A traffic shaper typically delays excess traffic using a buffer, or queueing mechanism, to hold packets and shape the flow when the data rate of the source is higher than expected. It holds and shapes traffic to a particular bit rate by using the token bucket mechanism. See the "Regulating Packet Flow Using Traffic Shaping" module.

Note GTS is similar to Class-Based Traffic Shaping. Although Class-Based Traffic Shaping is the Cisco-recommended mechanism, GTS is still supported.

GTS supports traffic shaping on most media and encapsulation types on the router.

GTS works with a variety of Layer 2 technologies, including Frame Relay, ATM, Switched Multimegabit Data Service (SMDS), and Ethernet.

GTS performs the following tasks:

•Applies traffic shaping on a per-interface basis and uses access control lists (ACLs) to select the traffic to shape.

•On a Frame Relay subinterface, dynamically adapts to available bandwidth by integrating backward explicit congestion notification (BECN) signals, or shapes to a specified rate. This is known as adaptive GTS.

•On an ATM/ATM Interface Processor (AIP) interface, responds to the Resource Reservation Protocol (RSVP) feature signalled over statically configured ATM permanent virtual circuits (PVCs).

Adaptive Generic Traffic Shaping on Frame Relay Networks

If adaptive GTS is configured on a Frame Relay network using the traffic-shape rate command, you can also use the traffic-shape adaptive command to specify the minimum bit rate to which the traffic is shaped.

With adaptive GTS, the router uses backward explicit congestion notifications (BECNs) to estimate the available bandwidth and adjust the transmission rate accordingly. The actual maximum transmission rate will be between the rate specified in the traffic-shape adaptive command and the rate specified in the traffic-shape rate command.

Configure these two commands on both ends of the network link, enabling the router at the high-speed end to detect and adapt to congestion even when traffic is flowing primarily in one direction.

For more information about configuring adaptive GTS, see the "Configuring Adaptive Generic Traffic Shaping for Frame Relay Networks" section.

Benefits of Generic Traffic Shaping

All of the benefits associated with traffic shaping also apply to GTS. For information about the benefits of traffic shaping, see the "Regulating Packet Flow Using Traffic Shaping" module.

How to Configure Generic Traffic Shaping

This section contains the following procedures. While all three procedures are listed as optional, you must choose either the first or the second procedure.

•Configuring Generic Traffic Shaping on an Interface (optional)

•Configuring Generic Traffic Shaping Using an Access Control List (optional)

•Configuring Adaptive Generic Traffic Shaping for Frame Relay Networks (optional)

Configuring Generic Traffic Shaping on an Interface

To configure GTS on an interface, complete the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. traffic-shape rate bit-rate [burst-size] [excess-burst-size] [buffer-limit]

5. end

6. show traffic-shape [interface-type interface-number]

7. show traffic-shape statistics [interface-type interface-number]

8. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number
Example:

Router(config)# interface s4/0

Configures an interface (or subinterface) type and enters interface configuration mode.

•Enter the interface type number.

Step 4

traffic-shape rate bit-rate [burst-size] [excess-burst-size] [buffer-limit]
Example:

Router(config-if)# traffic-shape rate 128000

Enables traffic shaping for outbound traffic on an interface based on the bit rate specified.

•Enter the bit rate.

Step 5

end
Example:

Router(config-if)# end

Returns to privileged EXEC mode.

Step 6

show traffic-shape [interface-type interface-number]
Example:

Router# show traffic-shape serial4/0

(Optional) Displays the current traffic-shaping configuration.

show traffic-shape statistics [interface-type interface-number]
Example:

Router# show traffic-shape statistics serial4/0

(Optional) Displays the current traffic-shaping statistics.

Step 7

exit
Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Configuring Generic Traffic Shaping Using an Access Control List

To configure GTS for outbound traffic using an access control list (ACL), complete the following steps.

Access Control List Functionality

Access control lists filter network traffic by controlling whether routed packets are forwarded or blocked at the router interface. When configured with GTS, the router examines each packet to determine how to shape the traffic on the basis of the criteria you specified for the access control list.

Access control list criteria could be the source address of the traffic, the destination address of the traffic, the upper-layer protocol, or other information. Note that sophisticated users can sometimes successfully evade or fool basic access control lists because no authentication is required.

SUMMARY STEPS

1. enable

2. configure terminal

3. access-list access-list-number {deny | permit} source [source-wildcard]

4. interface type number

5. traffic-shape group access-list bit-rate [burst-size [excess-burst-size]]

6. end

7. show traffic-shape [interface-type interface-number]

8. show traffic-shape statistics [interface-type interface-number]

9. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

access-list access-list-number {deny | permit} source [source-wildcard]
Example:

Router(config)# access-list 1 permit 192.5.34.0 0.0.0.255

Shapes traffic according to specified access list.

•Enter the access list number, one of the required keywords, and the source information.

Step 4

interface type number
Example:

Router(config)# interface s4/0

Configures an interface (or subinterface) type and enters interface configuration mode.

•Enter the interface type number.

Step 5

traffic-shape group access-list bit-rate [burst-size [excess-burst-size]]
Example:

Router(config-if)# traffic-shape group 101 128000

Enables traffic shaping based on a specific access list for outbound traffic on an interface.

•Enter the access list number and the bit rate.

Step 6

end
Example:

Router(config-if)# end

Returns to privileged EXEC mode.

Step 7

show traffic-shape [interface-type interface-number]
Example:

Router# show traffic-shape serial4/0

(Optional) Displays the current traffic-shaping configuration.

Step 8

show traffic-shape statistics [interface-type interface-number]
Example:

Router# show traffic-shape statistics serial4/0

(Optional) Displays the current traffic-shaping statistics.

Step 9

exit
Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Note Repeat the above procedure for each additional type of traffic you want to shape.

Configuring Adaptive Generic Traffic Shaping for Frame Relay Networks

To configure adaptive GTS for Frame Relay networks, complete the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. traffic-shape rate bit-rate [burst-size] [excess-burst-size] [buffer-limit]

5. traffic-shape adaptive bit-rate

6. traffic-shape fecn-adapt

7. end

8. show traffic-shape [interface-type interface-number]

9. show traffic-shape statistics [interface-type interface-number]

10. exit

DETAILED STEPS

Command or Action

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface type number
Example:

Router(config)# interface s4/0

Configures an interface (or subinterface) type and enters interface configuration mode.

•Enter the interface type number.

Step 4

traffic-shape rate bit-rate [burst-size] [excess-burst-size] [buffer-limit]
Example:

Router(config-if)# traffic-shape rate 128000

Enables traffic shaping for outbound traffic on an interface based on the bit rate specified.

•Enter the bit rate.

Step 5

traffic-shape adaptive bit-rate
Example:

Router(config-if)# traffic-shape adaptive 64000

Configures a Frame Relay subinterface to estimate the available bandwidth when BECNs are received.

•Enter the bit rate.

Step 6

traffic-shape fecn-adapt
Example:

Router(config-if)# traffic-shape fecn-adapt

Configures reflection of forward explicit congestion notifications (FECNs) as BECNs.

Step 7

end
Example:

Router(config-if)# end

Returns to privileged EXEC mode.

Step 8

show traffic-shape [interface-type interface-number]
Example:

Router# show traffic-shape serial4/0

(Optional) Displays the current traffic-shaping configuration.

Step 9

show traffic-shape statistics [interface-type interface-number]
Example:

Router# show traffic-shape statistics serial4/0

(Optional) Displays the current traffic-shaping statistics.

Step 10

exit
Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Configuration Examples for Generic Traffic Shaping

This section contains the following examples:

•Generic Traffic Shaping on an Interface Configuration: Example

•Generic Traffic Shaping Using an Access Control List Configuration: Example

•Adaptive Generic Traffic Shaping for a Frame Relay Network Configuration: Example

Generic Traffic Shaping on an Interface Configuration: Example

The following is an example of GTS configured on serial interface s4/0:

enable
configure terminal
interface s4/0
traffic-shape rate 128000
end
Generic Traffic Shaping Using an Access Control List Configuration: Example

The following is an example of GTS configured using an ACL. In this example, GTS is configured for the outbound traffic on ACL 1.

enable
configure terminal
access-list 1 permit 192.5.34.0 0.0.0.255
 interface s4/0 
traffic-shape group 101 128000
end
Adaptive Generic Traffic Shaping for a Frame Relay Network Configuration: Example

The following is an example of adaptive GTS configured on Frame Relay network. In this example, adaptive GTS is configured using the traffic-shape rate command. The traffic-shape adaptive command specifies the minimum bit rate to which the traffic is shaped. The actual maximum transmission rate will be between the rate specified in the traffic-shape adaptive command and the rate specified in the traffic-shape rate command.

enable
configure terminal
interface s4/0
  traffic-shape rate 128000
  traffic-shape adaptive 64000
  traffic-shape fecn-adapt
  end
Where to Go Next

To configure Class-Based Traffic Shaping, see the "Regulating Packet Flow on a Per-Class Basis — Using Class-Based Traffic Shaping" module.

To configure Frame Relay Traffic Shaping (FRTS), see the "MQC-Based Frame Relay Traffic Shaping" module.

Additional References

The following sections provide additional references related to configuring GTS.

Related Documents

Related Topic

Document Title

QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

Overview information about using traffic shaping to regulate packet flow on a network

"Regulating Packet Flow Using Traffic Shaping" module

Class-Based Traffic Shaping

"Regulating Packet Flow on a Per-Class Basis — Using Class-Based Traffic Shaping" module

FRTS

"MQC-Based Frame Relay Traffic Shaping" module

Standards

Standard

Title

No new or modified standards are supported, and support for existing standards has not been modified.

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MIBs

MIB

MIBs Link

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

No new or modified RFCs are supported, and support for existing RFCs has not been modified.

—

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Generic Traffic Shaping

Table 1 lists the release history for this feature

Not all commands may be available in your Cisco IOS software release. For details on when support for specific commands was introduced, see the command reference documents.

For information on a feature in this technology that is not documented here, see the "Regulating Packet Flow Roadmap."

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 1 Feature Information for Generic Traffic Shaping

Feature Name

Software Releases

Feature Configuration Information

This table is intentionally left blank because no features were introduced or modified in Cisco IOS Release 12.2(1) or later. This table will be updated when feature information is added to this module.

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